Method and apparatus for cleansing filter mediums.



A. L. GENTER. 1 METHOD AND APPARATUS FOR CLEANSING FILTER MEDIUMS. I

APPLICATION FILED Nov. 5. 1915.

Patented Jan. 30, 1917.,

v awwwtoz JM Z L. Gazai'm" TET @FEQ.

ALBERT LEGRAND GENTER, orsAL'r LAKE CITY, UTAH.

METHOD AND APPARATUS'FOR CLEANSING FILTER MEDIUMS.

Specification of Letters Patent.

Application filed November 5, 1915. Serial No. 59,882. 1

, fication.

filtering function.

My invention relates to a method of and apparatus for cleansing a filtermedium and the invention consists of the method andapparatussubstantially as hereinafter described and claimed.

In the accompanying drawirig forming part of this specification Iillustrate several forms of apparatus by which my process I may becarried out, but the invention is not restricted to such-apparatus or infact to any particular type of apparatus, as it is obvious that I mayresort to a variety of mechanical constructions and arrangements ofparts to obtain the desired results, as hereinafter specified.

Figure 1 is a part sectional view andpart elevation ofa filter cellhaving a filtrate outlet and a controlling member and embodying thesalient features of my invention. Fig.

.2 is a detail showing a changed position of the controlling member.Fig. 3 illustrates a modified form of apparatus showing a further meansof obtaining a back-pressure through the controlling member to theinterior of the filter leaf or cell. Fig. 4 illustrates a synchronousarrangement of two r0- tatiug valves, one designed to be timed to givefiltration pressure on the outside of a filterleaf or element when theother attached to the filtrate outlet is turned to a position releasinga back-pressure. Fig. 5 is a modification showing a means of connectinga rotat ing valve or' controlling member on the filtrate outlet so thatany accumulated cake cairbe vibrated, pulsated or knocked olf the filtermedium after the completion of the Fig. 6 is a modification of Fig. 1illustrating a. filter chamber havingrigid porous filter walls made ofporous stone, or other foraminous rigid material placed over corrugatedsides and bottom of the filter chamber.

The primary object of this invention is to increase the capacity of afiltering surface on such materials that have high resistance tofiltration, for instance colloids and such necessary to medium. Thiscommonly occurs in instances where a large amount of liquid has to beseparated from a small ainount of colloidal or finely divided solidsheld in suspension. In the said instance, the rate of flow of clearmaterial through the filtering medium is greater than the rate ofprecipitation of solids on the said medium and if the solids insuspension travel against the filter medium at the same velocityja-s theliquid being forced through the medium, the impact of solids against themedium is so great that they pack in tightly over the medium, therebyretarding the rate of filtration tosuch an extent that the initialoutflow of clear liquid through the medium rapidly drops to an extentwhere an enormous amount of area is meet the demands of a large,capacity. Any means that will prevent this packing of particles tightlyover the medium will more or less keep up the initial outflow offiltrate or clear liquid and materially reduce the'necessity of a largeamount of filter area, and if used in connection with filter presseswill give a thicker cake of solid material in a shorter time or at leastresult in a more copious capacity in outflow from the unit of filterarea. In this respect my invention .will simply and efficiently increasethe Patented Jan. 30, 191?.

capacity of any filter press under the same pressure and operatingconditions that are usual if it is attached to same. It also has otheradvantages in discharging the accu-.

when 111 one position the filtrate with the hydraulic or filtrationpressure back "of it is forced out through one valve opening into thecollecting launder, trough, or reservoir for same, and when in anotherposition the valve connects the filtrate channel or pipe with aback-pressure means, gas, liquid or otherwise, in such' a manner thatthe material on the filter medium is dislodgedor loosened by the shockor counter current, thus making the medium free for the followingoutrush of filtrate when the rotating or sliding valve turns to theposition where the back pressure is cut off and the filtrate underpressure is free to pass out into the open. If the valve is rotated orswitched rapidly, it stands to reason that the filtration willconsist ofintermittent pulsations I of clear liquid from the free opening of thevalve and an opposing series of intermittent back-pressure pulsations onthe interior of the filtering medium which pulsations hammer or pulsatethe accumulated material away from, or loosely hanging to, said me-,

dium so that the packing action 1s materially reduced and the solidsgradually accumulate in the filter cell or chamber instead of tightlypacking on the filter medium thus filtrate.

In the following description the filter medium is supposed to be ofexpansible character. This is ma nly to emphasize the illustration ofthe cleansing action. It is filtrate outlet, 6, which in its turn iscon-' nected to the rotating valve, 0. This valve is also connectedthrough one outlet with the pressure chamber, f, and through the otherwith the openoutlet, d. The material to be filtered is forced into thepressure or filter chamber, 2', through the ordinary means by way ofpipe or passage, a. 'Connected to the fluid pressure chamber, f, is thepressure inlet, 9-.

In the form of apparatus shown in Fig. 1, if the material to be filteredis forced into the chamber, 2, under pressure, the

filtrate penetrates the sides k of thefilter element, 72., and passesout through the pipe, I), and through the open position of the rotatingplug, j, of the valve, 0, and finally is delivered through the dischargeopening, d, as shown. During this operation the I pressure that existsin the chamber, f, is cut oil. from connection with the pipe, 6, and

interior of the filter element so that the filtrate is fr'ee to pass fora short timeout permitting a free outflow of of discharge, d.. If theplug, 3', of the valve, 0, is now switched or rotated into the positionshown in Fig. 2, the pressure that exists in the fluid pressure chamber,f, opposes the filtration pressure in the pipe, I), in such a way thatthe interior of the filter element, It, suffers a shock due to thecounter current induced through connecting the pressure chamber, 7',with the pipe, I), so that if the filter element has its sides formed offlexible material, these sides will distend into the dotted position,is. If the sides are rigid they will withstand the shock although thefilm of accumulating material on thesides will, in taking up the shock.try to assume the position indicated by it and thus be dislodged fromthe rigid sides of the filter element. If it be now assumed that theplug, j, of the valve, 0, is rapidly switched or rotated from oneposition to the other and that the filtrate outlet, 6, is kept full offiltrate at all times during filtration, the filtration pressure on oneside of the filter element and the back pressure on the other sidethereof will result in a piston action of the filtrate in the pipe, 6,moving forward on the one hand through the free outlet, (Z, andsuffering a shock on the other hand through being connected with theback pressure in the chamber, f, that will produce a vibrating orpulsating motion on the flexible or rigid sides of the filter element,keepingthe pores of the same free from packed material and causing anintermittent delivery of filtrate collected in the pipe, I), out throughthe discharge, (1.

It is clear that the back pressure means contemplated in Fig. 1 asentering the chamber, f, through the pipe, y, can be gained if thefiltrate passing through the pipe, 6, is .collected in a long cylinder,f (see 3), and permitted to outflow through a pipe, 9, before the plug,7', is rotated 01: vibrated. The hydrostatic back pressure exerted bythe weight of the filtrate in the cylinder, f, will then automaticallygive substantially the back pressure means provided in the pressurechamber, f, Fig. 1. Theaction of' this hydrostatic column then the sameduring filtration when the" plug, 7', of the valve 0, is rapidly rotatedor switched as has already been described.

IT the accumulatedfiltrate in the cylinder,

f, will exert a hydrostatic back pressure on the inside of the filterelement, It, when the plug, j, is in proper position, it is clear that asimilar column attached to the filter chamber inlet pipe, a, by means ofvalve, 0', and filled with the material to be filtered, which has agreater hydrostatic head than that exerted in the pressure chamber, f,will exert a hydrostatic filtration pressure on the opposite or outsideof thel-filtcr element, It.

This is illustrated inFigJ-i. If the two rotating plugs, j and 7", ofFig. 4, are so geared together and timed that when the plug, 1', it

in the open'position shown in Fig. 4, and'the plug, j is in the positionconnecting the column, f with the filter chamber, 2', it is clear thatthe excess hydrostatic pressure in the chamber, f. will cause filtrateto be forced through the filter and the pipes, b and d. If both plugsare, through gear or belt connections now switched or rotated into theopposite position, there will be an intermittent back or cleansingpressure exerted through the hydrostatic action in chamber, f, as hasalready been described, nection of the filter chamber, 2', with thepressure chamber, f, having in the meantime been disturbed through thevalve, j, assuming its new position. If this gear rotating device ofboth valves is worked rapidly enough, the intermittent filtering andback pressure action due to the two hydrostatic heads will not only givethe filtration usual with the ordinary filter pump and filter press, butalso give the pulsating cleansing action contemplated in my invention.This arrangement of synchronous vibrating parts does away with thenecessity of a special filter pump.

It is also obvious that this pulsating back pressure means can be usedespecially for dischargingthe accumulated cakes from any filter element,as is shown in Fig. 5. The idea here is to pulsate or knock or vibratethe cake, P, off of the filter medium after it has been collected on thesame through the ordinary filtration means. In Fi 5, the filter element,k with its outlet, bf, is supposed to be removed from the filter chamberand con: nected to a valve, 0 with its rotating plug, y' One outlet ofthe valve, 0', is connected to pressure line, m, and the other outlet iscennected to the suction or atmospheric line, a. It is clear'that if theplug, j is rapidly rotated, the gaseous or liquid pressure in thepressure .line will at one period enter the filter element,'-h tendingto expand same to dotted position, and the pressure then existing in thefilter element, h will be released the minute the-pressure in saidelement, b and pipe, 6 is connected through the plug rotation with thesuction line, n. This alternating expanding and deflating of theforaminous sides of'the filter element, 72,

together with the cleansing action of the gaseous or liquid pressuremeans in the line, m, and pipe, 6 will result in a series of that willeasily dislodge or blow the cake, I, from the filter element. In factpractice has shown that, this method of cleaning the filter medium ofaccumulated cake is much more thorough and cfiicient than the ordinarycontinuous back pressure action contemplated in known prior art.

In order to'defiate the distended sides or side of the filter elementinstead of connecting the one outlet of the valve, 0 with the the con-'springs, 0, bearing against the filter medium can be used. Thisarrangement is a valuable aid in accomplishing or making the vibra torymotion of the filter medium more pron'ounced, which, of course, will benecessary in certain instances.

As hereinbefore mentioned, it is obvious that the pulsatingback-pressure means can be used just as effectively on a filter mediumwith rigid sides. In Fig. 6, a filter chamber, 71", with rigid filterlining, h is shown in its simplest form. The sides, 11.3, of the filterchamber are corrugated so as to conduct the filtrate passing through therigid medium, 72?, to outlet, 1), and rotating valve, 0. The sides beingrigid will withstand the pulsating shock which will be transferred tothe much less rigid film, 7.1 of accumulated material adhering to sameand as a result this film will be dislodged from the rigid sides of thefilter element.

'Having thus described my invention what I claim as new and desire tosecureby Letters Patent is g I v 1. The process substantially as hereindescribed, of cleansing a filter medium and facilitating the filteringfunction thereof, said process consisting, essentially, in alternatelydirecting in substantially rapid succession the filter current againstone side of said medium and a cleansing current against the oppositeside of said medium.

2. The process substantially as herein described, of cleansing a filtermedium and facilitating the filtering function thereof, said processconsisting, essentially, in. imparting a positive movement to oppositesides of the filtering medium alternately.

3. The process substantially as herein described, of cleansing a filtermedium having flexible filtering sides and facilitating the filteringfunction of said sides, said process consisting, essentially, inimparting a positive rhythmical movement to the liquid by alternatepressures on q')posite sides of said medium.

4. The process substantlally as herein at;

scribed, of cleansing a filter medium having filtering sides andfacilitating the filtering function of said sides, said processconsisting, essentially, in imparting a series of intermittent filteringpulsations against the outer surface of said sides and alternatingtherewith an opposed series of intermittent back pressure pulsationsagainst the interior surfaces of said sides.

5. The process substantially as herein described, of cleansing a filter.medium and facilitating the filtering function thereof, said processconsisting, essentially, in giving alternate impulses to the filteringmedium in one direction and utilizing the back pressure of filtrateobtained from-a previous filtering period for giving alternate impulsesto the filtering medium in the opposite direction.

6. In apparatus of the character described, the combination with acasing and a filter element therein having pulsative filtering sides, ofa fluid-containing pressure chamber and a ported controlling memberbetween said casing and chamber connecting the interior of the filteralternately with the pressure chamber and with the atmosphere.

7. In apparatus of the character described, the combination with acasing and a filter element therein having pulsative filtering sides, of.a fluid-containing pressure chamber and a shiftable controlling memberbetween said casing and chamber having a port connecting the interior ofthe filter movement is imparted to the liquid on both sides of saidfiltering medium.

In testimony whereof I allix my signature.

ALBERT LEGRAND GENTEB.

